Phenoxy unsaturated carboxylic acid esters and derivatives

ABSTRACT

3-Alkoxy-4-substituted-phenoxy-2,3-unsaturated acid esters and derivatives thereof and the use thereof for the control of weeds.

This is a continuation-in-part of Ser. No. 270,938, filed June 5, 1981and Ser. No. 196,795, filed Oct. 14, 1980, each now abandoned, theentire disclosures of which are incorporated herein by reference.

This invention relates to 3-alkoxy-4-substituted-phenoxy-2,3-unsaturatedacid esters, derivatives thereof, and the use of said acid esters andderivatives for the control of weeds.

The novel 3-alkoxy-4- substituted-phenoxy-2,3-unsaturated acids, estersand derivatives thereof of the present invention are represented by thefollowing formulas A', B', C', and D': ##STR1## wherein, ##STR2##

W is O, S, NH or CH₂ ;

each of X and Y is independently selected from hydrogen, bromo, chloro,fluoro, lower alkyl, lower alkoxy, lower alkoxycarbonyl, nitro, cyano,trifluoromethyl, chlorodifluoromethyl, fluoromethyl, chloromethyl,difluoromethoxy;

n is 1 or 2;

each of X' and X" is independently selected from hydrogen, fluoro,chloro, bromo, iodo, trifluoromethyl, methoxy or nitro, provided thatboth X' and X" cannot be trifluoromethyl, methoxy or nitro;

R¹ is hydrogen or lower alkyl;

R² is lower alkyl;

Q is ##STR3## in which,

R³ is hydrogen, lower alkyl, lower haloalkyl, lower cyanoalkyl, loweralkenyl, lower haloalkenyl, lower alkynyl, lower alkoxyalkyl, lowerdialkylaminoalkyl, lower alkylthioalkyl, lower alkylsulfinyalkyl, loweralkylsulfonylalkyl, tetrahphofuranylmethyl, tetrahydropyranylmethyl,benzyl, halobenzyl, lower alkylbenzyl, lower alkoxybenzyl, phenyl,halophenyl, lower alkoxyphenyl, lower alkylphenyl,cycloalkyl,cycloalkalkyl, N- alkylideneamino, sodium, potassium,magnesium or calcium;

each of R⁴ and R⁵ is independently selected from hydrogen, lower alkyl,lower hydroxyalkyl, lower alkoxyalkyl or lower alkysulfonyl;

X³ is bromo, chloro, fluoro or iodo; and R⁶ is hydrogen or acyl.

In the description and claims hereinafter, each of R--R⁶, n, Q, W, X,X', X", X³ and Y is as defined above, unless otherwise specified.

The compounds of formula (A') wherein Q is ##STR4## can be produced bythe reaction of a phenol of formula (I). ##STR5## with a 4-halo compoundof formula (II) in the presence of a base such as alkali metal hydroxideor alkali metal carbonate. The reaction is generally conducted at aboutroom temperature to reflux temperature in an organic solvent such asdimethylformamide (DMF), acetone, tetrahydrofuran (THF),dimethylacetamide (DMA), dimethylsulfoxide (DMSO), or the like usingabout equimolar amounts of base, a phenol of formula (I) and a 4-halocompound of formula (II). X² represents bromo, chloro or iodo.

The thio compounds of formula (A') can be prepared starting with an acidof formula (A') which is converted into the acid halide and then reactedwith a mercaptan. Alternatively, a phenol of formula (I) is reacted witha 4-halo thiolester of the general formula (II) above in the presence ofbase.

An amide of formula (A') can be prepared by the reaction of an acidhalide of an acid of formula (A') with the appropriate amine.

An alcohol of formula (A') wherein Q is --CH₂ --OR⁶ can be prepared byreduction of an acid or ester of formula (A') using, for example,lithium borohydride or lithium aluminumhydride in ether or THF at a lowtemperature. Esters of an alcohol of formula (A') can be prepared by thereaction of an acyl halide or acyl anhydride in pyridine at about roomtemperature or lower.

A halide of the present invention of formula (A') wherein Q is --CH₂--X³ can be prepared by reaction of an alcohol of formula (A') wherein Qis --CH₂ --OH with phosphorus tribromide, phosphorus trichloride, ortriphenylphosphine dihalide in acetonitrile. In another embodiment ofthe present invention, there is provided 3-oxo derivatives of formula(B') which can be derived from the novel compounds of formula (A'). Thecompounds of formula (B') are useful for the control of weeds. ##STR6##

A compound of formula (B') can be prepared by the reaction of a 3-alkoxycompound of formula (A') such as a 3-methoxy compounds of formula (A')with an acid such as dilute perchloric acid or acetic acid in an organicsolvent such as methylenedichloride, tetrachloride or THF. The reactionis usually conducted at about room temperature or lower. In anotherembodiment of the present invention, there is provided compounds offormula (C') which can be prepared by selective reduction of a compoundof formula (B') using sodium borohydride in alcohol at low temperature.##STR7## The alcohols of formula (C') and carboxylic esters thereof areuseful for the control of weeds.

In another embodiment of the present invention, there is providedcompounds of formula (D') which are useful for the control of weeds.##STR8##

The compounds of formula (D') can be prepared by treating an alcohol offormula wherein Q is --CH₂ --OH with perchloric acid.

Carboxylic esters of formula (B') wherein Q is ##STR9## can be preparedby the following outlined method also: ##STR10##

The following terms have the meaning indicated as used herein and theappended claims.

The term "lower alkyl" refers to an alkyl group of one to six carbonatoms.

The term "lower alkoxy" refers to an alkoxy group of one to six carbonatoms.

The term "lower alkoxycarbonyl" refers to an alkoxycarbonyl group of twoto six carbon atoms.

The term "acyl" refers to a carboxylic acyl group such as loweraliphatic acyl group of one to six carbon atoms or aryl acyl group ofsix to twelve carbon atoms. Typical acyl groups include acetyl, benzoyl,p-chlorobenzoyl, and the like.

The term "lower alkenyl" refers to an alkenyl group of two to six carbonatoms with mono-unsaturation such as allyl and n-but-2-enyl.

The term "lower alkynyl" refers to an alkynyl group of two to six carbonatoms with monounsaturation such as propargyl.

The term "cycloalkyl" refers to a cycloalkyl group of three to sixcarbon atoms.

The term "cycloalkyl" refers to a cycloalkalkyl group of four to sevencarbon atoms.

The term "halo" refers to a bromo, chloro or fluoro group.

The compounds of formula A', B', C', D' are useful for the control ofweeds using pre- and/or post-emergent treatments. The compounds can beapplied in the form of dusts, granules, solutions, emulsions, wettablepowders and suspensions. Application of a compound of the presentinvention is made according to conventional procedure using from aboutone-half or less to ten pounds per acre. The application of a compoundof the present invention to the "locus" of the weeds includesapplication to the seeds, the plant (weed) or parts of the plant, or thesoil. Methods of preparing herbicidal formulations which can be usedwith a compound of the present invention are described in the literaturealong with suitable liquid and solid carrier materials such as in U.S.Pat. Nos. 4,192,669 and 4,163,661 which are incorporated herein byreference. While some of the compounds of the present invention haveactivity on broad leaf plants, the compounds, in general, demonstrate ahigher level of herbicidal activity on the grass weeds. The optimumusage of a compound of the present invention is readily determinable byone of ordinary skill in the art using routine testing such asgreenhouse testing and small plot testing.

The term "herbicide", as used herein, refers to an active ingredientwhich modifies the growth of plants because of phytotoxic or plantgrowth regulating properties so as to retard the growth of the plant ordamage the plant sufficiently to kill it.

The compounds of the present invention demonstrate selective activity asherbicides against grass weeds. Crops such as cotton, sugar beet,soybeans and squash show excellent tolerance. The compounds of thepresent invention, in general, show higher level of herbicidal activitywhen the postemergent method of application is used. Grass plant (weed)species on which the compounds of the present invention show effectiveherbicidal activity include shattercane, crabgrass, sprangletop, wildoats, bermudagrass, tall fescue, rice, wheat, barley, corn, bluepanicum, foxtails, rough bluegrass, winter rye, annual ryegrass,watergrass and Johnsongrass. It appears to be most effective to applythe active compound prior to the heading stage of the grass weed.

The compounds of the present invention, in view of their broadspectrumgrass weed herbicidal activity, can be advantageously combined withbroadleaf weed herbicides for broadspectrum postermergence weed controlin most broadleaf crops. Examples of herbicides which can be combinedwith a compound of the present invention include glyphosate, bentazone,diuron, paraquat, 2,4-D, 2,4-DB, diquat, endothal,dinoseb, dicamba,norflurazon, nitrofen, cyanozine, methazole, mefluidide, metribuzin,cycloate, fluometuron, linuron, dalapon, bifenox and alachlor forcontrolling a broad spectrum of weeds.

The compounds of the present invention are useful for application tosugarcane in order to increase the sucrose content of the sugarcane.

The following examples are provided to illustrate the practice of thepresent invention. Temperature is given in degrees centigrade. All partsare by weight unless otherwise indicated. RT means room temperature.

EXAMPLE 1

A mixture of 4-(2-chloro-4-trifluoromethylphenoxy) phenol (1.16 g),ethyl 4-bromo-3-methoxy-2-pentenoate (1.74 g) and potassium carbonate(0.73 g) in DMF (5 ml.) is heated at about 130° for 2 hours. Thereafter,DMF is removed. The residue is filtered and washed with methylenedichloride. The filtrate is washed, dried and evaporated to dryness. Theoily residue is subjected to prep. thin layer chromatography using 20%ethylacetate/hexane to yield the ethyl ester of4-[4-(2-chloro-4-trifluoromethylphenoxy) phenoxy]-3-methoxy-2-pentenoicacid, MS m/e 444 (M⁺).

EXAMPLE 2

A mixture of 4-(2-chloro-4-trifluoromethylphenoxy) phenol (6.9 mmol.),methyl 4-bromo-3-methoxy-2-pentenoate (8.9 mmol.) and potassiumcarbonate (1.5 equis.) in acetone (15 ml.) is refluxed for 48 hours.After filtration, the filtrate was concentrated and the residuechromatographed on silica gel using 20% ethylacetate/hexane to give themethyl ester of4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoicacid.

Some compounds of formula A' which are prepared according to theprocedure of the foregoing examples are as follows (Table I and II).

                  TABLE I                                                         ______________________________________                                         ##STR11##                                                                    X         Y       R.sup.1     R.sup.2                                                                            R.sup.3                                    ______________________________________                                        H         CF.sub.3                                                                              Me          Me   Me                                         H         CF.sub.3                                                                              Et          Me   Me                                         Cl        CF.sub.3                                                                              Et          Me   Me                                         Cl        CF.sub.3                                                                              Me          Et   Me                                         H         OCF.sub.3                                                                             Me          Me   Me                                         Cl        OCF.sub.3                                                                             Me          Me   Me                                         Cl        Cl      Me          Me   Et                                         NO.sub.2  CF.sub.3                                                                              Me          Me   Me                                         H         Br      Me          Me   Et                                         Me        OMe     Me          Me   Me                                         ______________________________________                                    

                  TABLE II                                                        ______________________________________                                         ##STR12##                                                                    X         Y       R.sup.1     R.sup.2                                                                            R.sup.3                                    ______________________________________                                        Cl        Cl      Me          Me   Me                                         H         CF.sub.3                                                                              Me          Me   Me                                         Cl        CF.sub.3                                                                              Me          Me   Me                                         H         CHF.sub.2                                                                             Me          Me   Me                                         H         CClF.sub.2                                                                            Me          Me   Me                                         Me        CF.sub.3                                                                              Et          Me   Et                                         F         CF.sub.3                                                                              Me          Me   Me                                         H         Br      Me          Me   Me                                         Cl        Cl      Me          Et   Et                                         Cl        Cl      Et          Et   Et                                         ______________________________________                                    

EXAMPLE 3

A mixture of the methyl ester of4-[4-(2-chloro-4-trifluoromethylphenoxy) phenoxy]-3-methoxy-2-pentenoicacid (0.5 g), 35% aqueous perchloric acid (5 ml.) and methylenedichloride (5 ml.) is stirred at RT for 4 days. Then the solution isextracted with methylene dichloride. The combined extracts are washed,dried and evaporated. The residue is purified by prep. thin layerchromatography using 20% ethyl acetate/hexane to yield methyl4-[4-(2-chloro-4-trifluoromethylphenoxy) phenoxy]-3- oxopentanoate.

The product of Example 1 is treated with aqueous perchloric acid asabove to yield ethyl 4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-oxopentanoate, MS m/e 430 (M⁺).

By use of the foregoing procedure, each of the compounds of Tables I andII are converted into the corresponding 3-oxocompound of formula (F)such as methyl 4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-oxopentanoate,methyl 4-[4-(4-trifluoromethoxy-phenoxy)phenoxy]-3-oxopentanoate, ethyl4-[4-(2,4-dichlorophenoxy)phenoxy]-3-oxopentanoate, MS m/e 396 (M⁺),methyl 4-[4-(4-dichlorophenoxy)phenoxy]-3-oxopentanoate, methyl4-[4-(3,5-dichloropyridyloxy)phenoxy]-3-oxopentanoate and methyl4-[4-(5-trifluoromethylpyridyloxy)phenoxy]-3-oxopentanoate.

EXAMPLE 4

A mixture of 4-(2-nitro-4-trifluoromethylphenoxy) phenol (9.36 mm).,ethyl 4-bromo-3-methoxy-2-pentenoate (12 mm.) and K₂ CO₃ (14 mm.) inacetone (20 ml.) is refluxed for 24 hours. After filtration, thefiltrate is concentrated and the oily residue chromatographed on silicagel to yield ethyl4-[4-(2-nitro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoate.

A solution of the above ethyl ester in 35% perchloric acid and water isstirred at RT for 3 days and then worked up to give ethyl4-[4-(2-nitro-4-trifluoromethylphenoxy) phenoxy-3-oxopentanoate.

EXAMPLE 5

To a mixture of lithium aluminum hydride (200 mg) and anhydrous ether (5ml.) is added dropwise at 0°, a mixture of ethyl4[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoate(400 mg) and ether (5 ml.). After addition is complete, the mixture isstirred for about minutes. Wet ether and water is added to destroyexcess hydride. Filtration and evaporation of filtrate gives4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-penten-1-ol.

EXAMPLE 6

A mixture of ethyl4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoate(10 mmol), ethanol (20 ml.) and 1 N Na OH (20 ml.) is prepared and thenheated at reflux for a few hours to complete the reaction. Removal ofsolvent gives the sodium salt of4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoicacid. The free acid is obtained by acidification of the salt usingdilute H₂ SO₄, and extraction with methylene dichloride and evaporation.Other acid salts can be prepared by titrating the free acid with anorganic solution of the base, e.g., methanolic solution of potassiummethoxide and the like.

EXAMPLE 7

Thionyl chloride (20 ml.) is added to4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoicacid (10 mm.) in anhydrous ether (10 ml.). The mixture is refluxed for afew hours. Then, ether and excess thionyl chloride is removed by vacuumto yield4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoylchloride.

EXAMPLE 8

To a mixture of 4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoyl chloride (10 mm.) and ether (10 ml.) isadded methyl mercaptan (12 mm.) and pyridine (1 ml.) at about -20°. Themixture is stirred for about 30 minutes and then allowed to rise toabout 0° and stand for about 2 hours. The mixture is then diluted withether and water and the ether phase separated, washed, dried and solventremoved to give the methylthiol ester of4-[4-(2-chloro-4-trifluoromethylphenoxy) phenoxy]-3-methoxy-2-pentenoicacid.

EXAMPLE 9

A mixture of 4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoyl chloride (15 mm) and THF (15 ml.), at 0°,is prepared and then slight excess of methylamine introduced. Thereaction mixture is allowed to stand under nitrogen for about one hour.Then the reaction is allowed to rise to RT and solvent removed. Theresidue is taken up in methylene dichloride, washed, dried and solventremoved under vacuum to yield N-methyl4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenamide.

EXAMPLE 10

A mixture of ethyl 3-oxopentanoate (20 g) and trimethylformate (5 eq.,94ml.) in the presence of 6 g of Amberlyst-15 (trademark of Rohm & HaasCorp.) is stirred at RT overnight. After filtration, the filtrate isconcentrated and then distilled to give ethyl 3-methoxy-2-pentenoate(19.5 g).

A mixture of the above ethyl ester, N-bromosuccinimide (26.3 g), benzoylperoxide (0.3 g.) and carbon tetrachloride (100 ml.) is heated to refluxand irradiated with 150 watt flood lamp until substantially clearsolution is obtained. Thereafter, the reaction is filtered and thefiltrate then concentrated and distilled (78°/2 mm) to give ethyl4-bromo-3-methoxy-2-pentenoate.

EXAMPLE 11

(A) Following the procedure of Example 1,4-(2-nitro-4-trifluoromethylphenylamino) phenol is reacted with ethyl4-bromo-3-methoxy-2-pentenoate to give ethyl4-[4-(2-nitro-4-trifluoromethylphenylamino)phenoxy]-3-methoxy-2-pentenoate

(B) Following the procedure of Example 3, the product of part (A) istreated with aqueous perchloric acid to give ethyl4-[4-(2-nitro-4-trifluoromethylphenylamino)phenoxyl]-3 oxopentanoate, MSm/e 512 (M⁺).

In the same way, there is prepared methyl 4-[4-(2-nitro-4-chlorophenylamino)phenoxy]-3-methoxy-2-pentenoate and methyl4-[4-(2-nitro-4-chlorophenylamino)phenoxy]-3-oxopentanoate starting with4-(4-chloro-2-nitrophenylamino) phenol and methyl4-bromo-3-methoxy-2-pentenoate.

EXAMPLE 12

A spray solution of water/acetone (1:1) and surfactant (1%) was preparedcontaining (1) the compound of Example 1 (Compound 1) and (2) the secondcompound of Example 3 (Compound 2) and sprayed (equivalent to 10lb/acre) on seedlings of foxtail (Setaria viridis) and watergrass(Echinochlou crusgalli). Observation two weeks after spraying Compound 1and 2 showed 100% herbicidal activity for each of test Compounds 1 and2. Testing of Compounds 1 and 2 showed no injury to soybeans at 10lb/acre.

Pre-emergent herbicidal activity of Compound 2 was tested on foxtail,watergrass, shattercane, and wild oats. The average activity was 86% forthe four species.

EXAMPLE 13

To a slurry of LiAIH₄ (100 mg) in anhydrous ether (20 ml) is addeddropwise at 0°, a solution of ethyl4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoate (500 mg)in ether. After addition is complete, the reaction mixture is stirredfor about 20 minutes. Excess of the hydride is decomposed using wetether and water. Filtration and evaporation of filtrate gives the C-1alcohol,4-[4-(4-trifluormethylphenoxy)phenoxy]-3-methoxy-2-penten-1-ol,MS m/e 440 (M⁺).

EXAMPLE 14

To a slurry of LiAlH₄ (200 mg) in anhydrous ether (15 ml) is added at 0°a solution of ethyl4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-oxopentanoate(400 mg) in ether(5 ml). After addition is complete, the reaction mixture is stirred atRT for about one hour. Excess of the hydride is decomposed using wetether and water, the mixture is filtered and filtrate concentrated. Theoily product is purified by prep. thin layer chromatography to give4-[4-(4-trifluoromethylphenoxy)phenoxy]-pentane-1,3-diol, MS m/e 500(M⁺).

EXAMPLE 15

To a solution of ethyl 4-[4-(2-nitro-4-chlorophenoxy)phenoxyy]-3-oxopentanoate (600 mg) in absolute ethanol (10 ml) is addedat 0°, NaBH₄ (300 mg). After addition is complete, the reaction mixtureis stirred for about 20 minutes. Then the solution is taken up in CH₂Cl₂, washed with brine, dried and evaporated to give ethyl4-[4-(2-nitro-4chlorophenoxy)phenoxy]-3-hydroxypentanoate.

EXAMPLE 16

To a slurry of LiAlH₄ (400 mg) in anhydrous ether (20 ml) is addeddropwise at 0°, a solution of ethyl4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoate (1.2 g)in ether (10 ml). After addition is complete, the reaction mixture isstirred for about 10 minutes. Excess hydride is decomposed with wetether and water. After filtration, the filtrate is concentrated to givethe alcohol, 4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-penten-1-ol.

The alcohol (600 mg) is stirred with 5 ml of 35% HClO₄ in CH₂ Cl₂ (5 ml)for about 20 minutes. The solution is then extracted with CH₂ Cl₂followed by washing, drying and evaporation. The product is thenpurified by prep. thin layer chromatography to give4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-oxo-1-pentene, MS m/e 336(M⁺).

EXAMPLE 17

To a solution of ethyl 4-[4-(4trifluoromethylphenoxy)phenoxy]-3-oxopentanoate (450 mg) in ethanol (5 ml) is added NaBH₄ (150mg) at 0°. The resulting mixture is then stirred at 0° for about 10minutes. The mixture is diluted with CH₂ Cl₂, washed with saturated NaClsolution, dried and evaporated to dryness to give ethyl4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-hydroxypentanoate, inquantitative yield, MS m/e 398 (M⁺).

EXAMPLE 18

The process of Example 17 is repeated using ethyl4-[4-(2chloro-4trifluoromethylphenoxy)phenoxy]-3-oxopentanoate (400 mg)and NaBH₄ (100 mg) to give ethyl4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-hydroxypentanoate, MSm/e 432 (M⁺).

EXAMPLE 19

To a slurry solution of LiAlH₄ (200 mg) in anhydrous ether (5 ml) isadded dropwise at 0°, a solution of ethyl4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-pentenoate(400 mg) in anhydrous ether (5 ml). After addition is complete, thereaction mixture is stirred at 0° for about 10 minutes. Excess hydrideis decomposed with wet ether and water. The mixture is filtered andfiltrate washed, dried and evaporated to give4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-methoxy-2-penten-1-ol.

The foregoing alcohol (380 mg) is reacted with 35% HClO₄ (4 ml) in CH₂Cl₂ (4 ml) at RT for 24 hours. The mixture is then extracted with CH₂Cl₂ and the combined extracts washed, dried and concentrated to dryness.The product is purified by prep. thin layer chromatography to give4-[4-(2-chloro-4trifluoromethylphenoxy)phenoxy]-3-oxo-1-pentene, MS m/e396 (M⁺).

EXAMPLE 20

A solution of 2-[4-(4-trifluoromethylphenoxy)phenoxy]-propionyl chloride(1.5 g) and methylene chloride (5 ml) is added dropwise at 0° to asolution of 2,2-dimethyl-1,3-dioxane-4,6-dione (680 mg) in methylenechloride (20 ml) containing pyridine (0.7 ml). The resulting mixture isstirred at RT for 2 hours. The reaction mixture is then poured intowater, acidified with dilute HCl and extracted with methylene chloride.The combined extracts are washed with brine, dried and evaporated togive 2-[4-(4trifluoromethylphenoxy)phenoxy]-propionyl meldrum acid, anoil.

The above meldrum acid is treated with n-butanol (20 ml) at 120° forabout 4 hours. After aqueous workup, the oily concentrate is purified byprep. thin layer chromatography on silica gel to give n-butyl4-[4-(4-trifluoromethylphenoxy) phenoxy]-3-oxopentanoate, MS m/e 424(M⁺).

EXAMPLE 21

A mixture of 2-nitro-3-trifluoromethyl-4'-hydroxydiphenylamine (1 g),ethyl 4-bromo-3-methoxy-2-pentenoate (990 mg) and potassium carbonate(694 mg) in acetone (10 ml) is refluxed for 24 hours. After filtrationand concentration, the crude product is purified by prep. thin layerchromatography on silica gel to give ethyl4-[4-(2-nitro-4-trifluoromethylanilino)phenoxy]-3-methoxy-2-pentenoatewhich is treated with 35% HClO₄ in methylene chloride to give ethyl4-[4-(2-nitro 4-trifluoromethylanilino)phenoxy]-3-oxopentanoate, MS m/e440 (M⁺).

EXAMPLE 22

Post-emergence activity on the grasses (GR) greenfoxtail, watergrass,shattercane and wild oats was tested for the compound of Examples 13,14, 17, 18, 20 and 21 (compounds No. 3, 4, 5, 6, 7 and 8, respectively)and on the broadleafs (BL) annual morningglory, sesboria, soybean andvelvet leaf by spraying at rate equivalent to 10 lb/acre. The averagescore is given in percent control.

    ______________________________________                                        Compound No.       GR     BL                                                  ______________________________________                                        3                  100    14                                                  4                   96    8                                                   5                  100    11                                                  6                  100    3                                                   7                  100    7                                                   8                  100    0                                                   ______________________________________                                    

EXAMPLE 23

An emulsifiable concentrate was prepared having the followingcomposition (components in percent by weight).

    ______________________________________                                        (VI)      Compound B  27.78                                                             Igepol CO-530                                                                             2.67                                                              Tween 21    2.67                                                              Tween 81    2.67                                                              Corn oil    64.21                                                   ______________________________________                                    

Compound B is ethyl4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-oxopentanoate (90% purity).Tween 21 is non-ionic surfactant, polyoxyethylene sorbitan monolaurateand Tween 81 is polyoxyethylene sorbitan monooleate. Tween is atrademark of ICI Americas. Igepal CO-530 is a non-ionic surfactant[nonylphenoxypoly(ethyleneoxy)ethanol] of GAF, Inc.

    ______________________________________                                        (VII)      Compound C   29.3                                                             Toximol S    6.4                                                              Atlox 8916 TF                                                                              1.6                                                              Tenneco 500-100                                                                            62.7                                                  ______________________________________                                    

Compound C is ethyl 4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-hydroxypentanoate (90% purity).

A spray solution was prepared using 30 parts of concentrate VII, 950parts of water and 28 parts of nonphytotoxic crop oil and applied toyoung Johnson grass at the rate of 1.0 lb. per acre. The test plots wereobserved after two weeks. The application gave 100% control of theJohnson grass.

    ______________________________________                                        (VIII)     Compound B   27.8                                                             Toximol R    3.0                                                              Toximol S    9.0                                                              Tenneco 500-100                                                                            60.2                                                  ______________________________________                                    

Concentrate VIII was diluted in water and applied at the rate of 2.0 lb.per acre to test specimens, in a greenhouse, of watergrass, greenfoxtail, shattercane, blue panicum, tallfescue, spangletop, annualryegrass, downy brome, wild oats, crabgrass, milo, corn, probred wheatand barley. The average herbicidal activity of two or more evaluationsof each of the foregoing grass species was 80% or greater.

Toximol R and S are surfactants of the Stepan Chemical Corporation,Illinios. Atlox 8916F in a surfuctant of ICI Americas, Delaware. Tenneco500-100 is an aromatic solvent of the Tenneco Corporation.

EXAMPLE 24

Flowable formulations were prepared having the following compositions,percent by weight.

    ______________________________________                                        (XI)      (A)    Compound B  3.00                                                              Toximol 360A                                                                              3.00                                                              Sun 7N (oil)                                                                              30.00                                                      (B)    Water       60.85                                                             Gelvatol 20/30                                                                            3.00                                                              Kelzan      0.15                                             ______________________________________                                    

Premix (A) was dispersed in high speed blender for about one minute andthen Premix (B) was poured into Premix (A) while stirring at high speed.After addition of Premix (B) stirring was continued about 5 minutes.

    ______________________________________                                        (X)       (A)    Compound C  3.00                                                              Toximol 360A                                                                              3.00                                                              Sun 7N      30.00                                                      (B)    Water       60.85                                                             Gelvatol 20/30                                                                            3.00                                                              Darvan No. 1                                                                              0.15                                             ______________________________________                                    

Premix (A) and (B) were combined as described for flowable IX above.Concentration of active ingredient 2.7%.

Sun 7N is a non-phytotoxic oil of the Sun Chemical Company. Gelvatol20/30 is a polyvinyl alcohol, molecular weight about 10000 of theMonsanto COmpany. Kelzan is a thickener agent (xanthum gum). Darvan No.1 is a dispersant of the RT Vanderbilt Company.

EXAMPLE 25

The compound, 2-[4-(4-trifluoromethylphenoxy)-phenoxy]propionyl meldrumacid (V; W is oxygen, R is 4-trifluoromethylphenyl, and R¹ is methyl) isreacted with the alcohol R³ -OH using the procedure of Example 20 toprepare the respective ester under Table III.

                  TABLE III                                                       ______________________________________                                         ##STR13##                                                                            R.sup.3                                                               ______________________________________                                                CH.sub.2CN                                                                    CH.sub.2CHCH.sub.2                                                            CH.sub.2CHC Cl.sub.2                                                          CH.sub.2CCH                                                                   CH.sub.2CH.sub.2OCH.sub.3                                                      ##STR14##                                                                    CH.sub.2CH.sub.2Cl                                                             ##STR15##                                                                    CH.sub.2CH.sub.2SCH.sub.2CH.sub.3                                              ##STR16##                                                                     ##STR17##                                                                     ##STR18##                                                                     ##STR19##                                                                     ##STR20##                                                                     ##STR21##                                                                     ##STR22##                                                                     ##STR23##                                                            ______________________________________                                    

EXAMPLE 26

Following the procedure of Example 17, each of the 3-oxo esters underTable III is reduced using sodium borohydride to yield the respective3-hydroxy esters of the following formula: ##STR24##

EXAMPLE 27

Ethyl 4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-hydroxypentanoate isreacted with 1.1 equivalent of acetyl chloride and 1.0 equivalent ofpyridine in benzene to yield ethyl4-[4-(4-trifluoromethylphenoxy)phenoxy]-3-acetoxypentanoate. Similarly,using n-propanoyl chloride and isopropanoyl chloride yield therespective 3-n-propanate and 3-isopropanoate.

Carbonates of the 3-hydroxy compounds of formula C' are prepared usingthe above procedure and 1.1 equivalents of, for example, ethylchloroformate or methyl chloroformate. The 3-carbonates are usefulherbicides for grass weeds also.

In the preparation of the 3-hydroxy compounds of formula C', in additionto reduction of the respective 3-oxo compound of formula B', the3-hydroxy compounds such as the esters can be prepared by the followingoutlined method. ##STR25##

The compounds of the present invention include the isomeric forms andmixtures thereof. Thus, the invention includes the optically activeisomers and racemic mixtures. Unless otherwise specified herein, thecompounds described in the examples are racemic mixtures.

EXAMPLE 28

Each of the compounds, methyl4-[4-(3,5-dickloropyridyloxy)phenoxy]-3-oxopentanoate and methyl4-[4-(5-trifluoromethylpyridyloxy)phenoxy]-3-oxopentanoate is reactedwith NaBH₄ by the procedure of Example 17 to yield methyl4-[4-(3,5-dichloropyridyloxy)phenoxy]-3-hydroxypentanoate and methyl4-[4-(5-trifluoromethylpyridyloxy)phenoxy]-3-hydroxypentanoate,respectively.

EXAMPLE 29

The process of Example 20 is repeated with the exception of using2-[4-(6-chloro-2-quinolinyloxy)phenoxy]-propionyl chloride as thestarting material in place of2-[-(4-trifluoromethylphenoxy)phenoxy]-propionyl chloride to yield asthe final product, n-butyl4-[4-(6-chloro-2-quinolinyloxy)phenoxy]-3-oxopentanoate.

By using 2-[4-(6-fluoro-2-quinolinyloxy)phenoxy]-propionyl chloride asthe starting material and ethyl alcohol in place of n-butyl alcohol inthe process of Example 20, there is obtained ethyl4-[4-(6-fluoro-2-quinlinyloxy) phenoxy]-3-oxopentanoate which is reducedusing NaBH₄ in alcohol to yield ethyl 4-[4-(6-fluoro-2-quinolinyloxy)phenoxy]-3-hydroxypentanoate.

EXAMPLE 30

The compound, 6-fluoro-2-(4-hydroxyphenoxy) quinoxaline, is used as thestarting material in Example 1 in place of4-(2-chloro-4-trifluoromethylphenoxy)phenol to yield ethyl4-[4-(6-fluoro-2-quinoxalyloxy)phenoxy]-3-methoxy-2-pentenoate which isreacted with aqueous perchloric acid by the process of Example 3 toyield ethyl 4-[4-(6-fluoro-2-quinoxalyloxy)phenoxy]-3-oxopentanoate. The3-oxo ester on reduction with NaBH₄ yield the 4-hydroxy ester, ethyl4-[4-(6-fluoro-2-quinoxalyloxy)phenoxy]-3-hydroxypentanoate.

What is claimed is:
 1. A compound of the formula ##STR26## wherein W isoxygen, R¹ is hydrogen or lower alkyl and each of X and Y isindependently selected from hydrogen, bromo, chloro, fluoro, loweralkyl, lower alkoxy, lower alkoxycarbonyl, nitro, cyano,trifluoromethyl, chlorodifluoromethyl, fluoromethyl, chloromethyl anddifluoromethoxy.
 2. A compound according to claim 1 wherein R¹ is methyland X is hydrogen, chloro or nitro and Y is trifluoromethyl or chloro.3. A compound according to claim 2 wherein X is hydrogen or chloro. 4.The compound, 4-[4-(4-trifluoromethyl phenoxy)phenoxy]-3-oxo-1-pentene,according to claim
 1. 5. The compound,4-[4-(2-chloro-4-trifluoromethylphenoxy)phenoxy]-3-oxo-1-pentene,according to claim 1.